SpaceX's Falcon Heavy is not just for big payloads, it can also throw light things into space very fast. And that has significant implications for the exploration of distant destinations in our outer solar system—particularly the ocean moons of the giant planets.

Tomorrow, Cassini will fly by Titan, picking up a gravity assist that will tilt its orbit slightly up and out of the ring plane. That will end what has been a wonderful year of frequent encounters with Saturnian moons.